Airlines 'knew blood clot risk'

Airlines have been criticised for not explaining the risks

Airlines have known about the possible links between long-haul flights and deep vein thrombosis (DVT) for 10 years, a BBC investigation has found.

BBC One's Panorama programme also says that dozens of airlines turned down or ignored requests from scientists to study blood clots among passengers.

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One recent study has suggested that as many as one in 10 long-haul passengers could be at risk from DVT, commonly called "economy class syndrome".

DVT is a condition in which a small, potentially fatal blood clot forms, often in the deep veins of the legs.

Emma Christofferson: Died after 20-hour flight

It becomes potentially deadly when a part of the clot breaks off and blocks a blood vessel in the lungs.

Scientists believe there is a risk connected to flying because of the long hours a passenger remains immobile.

The problem came to public notice following high-profile cases like that of 28-year-old Emma Christofferson, from south Wales, who died after a 20-hour flight from Australia.

She suffered a massive blood clot after sleeping for most of the journey, and collapsed and died shortly after arriving at Heathrow Airport last October.

Health advice

Pressure was put on the airlines to warn passengers on the risks of sitting still for too long and to provide health and safety advice.

But Panorama says that airlines knew about the possible links 10 years ago.

There are no accurate figures telling us how many people die from flight-related blood clots

John Scurr
Vascular surgeon

While they did offer advice to passengers, they did not specifically refer to DVT or potentially fatal blood clots.

When asked why, one airline said it did not want to confuse or alarm passengers.

Vascular surgeon John Scurr told the BBC that flight-related DVT could be responsible for as many as 1,000 deaths every year.

"There are no accurate figures telling us how many people die from flight-related blood clots," he said.

"But I would estimate that it is certainly in excess of a few hundred and possibly up to as many as 1,000 people a year.

"That is based on our experience from hospitals in close proximity to airports."

Panorama: Economy Class Syndrome can be seen on BBC One at 2215BST on Sunday.